Surface sensing utilizes a surface condition or a change in a surface condition to measure a physical property of a test medium. In one surface sensing application, changes in the refractive index at the surface of a sensor can be measured. In another surface sensing application, surface conditions which increase the directionality of fluorescence can be used to detect a fluorescent material.
A surface sensor has been fabricated on the end of an optical fiber to create a single surface sensor that can be used, for example, to perform in-situ sensing. Although a single surface sensor located on the end of an optical fiber enables in-situ sensing, the throughput of the single surface sensor is limited to one test per fiber. The throughput of surface sensing systems is often a critical factor in achieving commercially viable sensing products.